From: Florian Westphal <fw@xxxxxxxxx>
This patch has been added to the 3.12 stable tree. If you have any
objections, please let us know.
===============
[ Upstream commit 6d39d589bb76ee8a1c6cde6822006ae0053decff ]
In case of tcp, gso_size contains the tcpmss.
For UFO (udp fragmentation offloading) skbs, gso_size is the fragment
payload size, i.e. we must not account for udp header size.
Otherwise, when using virtio drivers, a to-be-forwarded UFO GSO packet
will be needlessly fragmented in the forward path, because we think its
individual segments are too large for the outgoing link.
Fixes: fe6cc55f3a9a053 ("net: ip, ipv6: handle gso skbs in forwarding path")
Cc: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Reported-by: Tobias Brunner <tobias@xxxxxxxxxxxxxx>
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
net/core/skbuff.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 21571dc4f2df..f69f2ed1dbc3 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3535,12 +3535,14 @@ EXPORT_SYMBOL_GPL(skb_scrub_packet);
unsigned int skb_gso_transport_seglen(const struct sk_buff *skb)
{
const struct skb_shared_info *shinfo = skb_shinfo(skb);
- unsigned int hdr_len;
if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))
- hdr_len = tcp_hdrlen(skb);
- else
- hdr_len = sizeof(struct udphdr);
- return hdr_len + shinfo->gso_size;
+ return tcp_hdrlen(skb) + shinfo->gso_size;
+
+ /* UFO sets gso_size to the size of the fragmentation
+ * payload, i.e. the size of the L4 (UDP) header is already
+ * accounted for.
+ */
+ return shinfo->gso_size;
}
EXPORT_SYMBOL_GPL(skb_gso_transport_seglen);
--
1.9.3
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